Single chain gripper



Dec. 11, 1956 J. R. CAULFIELD SINGLE CHAIN GRIPPER Filed July 27, 1953 INVENTOR. JOS-EPH R. CAULFIELD (a By ATTORNEY SINGLE CHAIN GRIPPER Application July 27, 1953, Serial No. 370,541 12 Claims. (Cl. 198 -180) This invention relates to positively driven grippers for moving'sheets of paper, cardboard and the like, and more particularly to an improved gripper which is built into and carried by a single chain. A I

There aremany situations in which it isnecess'ary to rapidly feed single sheets in succession. This may be done by means of superposed belts driven at identical speed and between which the sheets are carried. However, there are other situations in which 'a more positive feed is needed, and in which it is preferred to actually grip the leading edge of the sheet between gripper jaws, and to positively move the grippers by means of chains.

Such chain-carried grippers havealready been used, but the grippers usually have been carried between two spaced chains disposed collaterally and moved in unison. Such an arrangement has a number of drawbacks. One is that it'is not well adapted to be interleaved with belts. for feeding the sheets to the grippers, or for removing the sheets from the grippers. For that purpose it isdesirable that the belts and chains, although arranged generally in tandem, be overlapped somewhat so that the belts terminate some distance after the chains begin, or vice versa.

Another disadvantage of grippers carried between multiple chains is that the chains may wear unequally. This difficulty is'aggravated because it is not possible to lubricate the chains in the usual way, inasmuch as they are disposed over the sheets, and every precaution must be taken against lubricant dropping on to thesheets,

Chain carried grippers have also proved troublesome because of rapid wear of the chains resulting from the use of special parts, particularly the pins and rollers, which are not as well designed and made for the purpose as are the regular pins and rollers of thefchain as made by the chain manufacturer, who has a considerable background and experience in respect to the proper steeLthe machining and hardening treatment thereof.

The primary object of the present invention is to generally improve chain carried grippers, and to overcome the foregoing difficulties and disadvantages. For this purpose I have designed a gripper which may be built into, carried by, and form a part of a single chain. The chain is preferably a standard roller chain utilizing standard pins and rollers. Even at the gripper the pins. and rollers are standard, although the standard links are replac'ed'there by special links, but even these are of such a character that they may be made by the chain manufacturer on special order.

The gripper assembly employs a pivot pin for 'movable gripper jaws, and may have a cam roller .pin to carry one or two cam rollers to move said jaws. In order to keep the gripper assembly compact and close to the chain line, yet symmetrically disposed with respect to amidplane passing through the chain perpendicular to the United States Patentce of inner links '32 "replacing the standard inner links 26.

sprocket wheel axis, these pins may be disposed at or e close'to the common plane of the chain roller axes. This, however, may result in interference with the teeth of the sprocket wheels,-if conventional sprocket wheels are employed; with one sprocket tooth "occupying: the: space he- 2,773,585 Patented Dec. 11, 1956 this difiiculty, which is done by locating the pins halfway between the chain rollers; by making them smaller in diameter than the chain rollers; and by using sprocket.

wheels having a pitch between teeth which is only half of the pitch of the chain. Thus two teeth enter the space between successive rollers, and when a gripper reaches the sprocket wheel the extra pivot pin and cam roller pin enter the spaces between the pairs of sprocket wheel teeth.

To accomplish the foregoing general objects, and other more specific objects which will hereinafter appear, my invention resides in the single chain gripper elements, and their relation one to another, as are hereinafter more particularly described in the following specification. The specification is accompanied by a drawing, in which:

Fig. l is a plan view of a fragment of roller chain carrying a gripper; I

Fig. 2 is a side elevation thereof;

Fig. 3 is a transverse section taken approximately in the plane of the line 3-3 of Fig. 1;

Fig. 4 is a sideelevation similar to Fig. 2, but showing the gripper open;

Fig. 5 is a vertical section through a gripper at a sprocket wheel, and shows how clearance is provided for extra pins required at the gripper;

Fig. 6 is a plan view similar to Fig. 1, but showing a modified gripper having only one cam roller;

Fig. 7 is a side elevation of the same;

Fig. 8 is a section throughthe gripper at a sprocket wheel, and shows one method of opening the gripper jaws;'and

Fig. 9 is a side elevation showing a delivery system utilizing the gripper of the'present invention.

Referring to the drawing, and more particularly Figs. 1 through 4, a single endless chain generally designated 12, carries gripper jaws 14, 16 dispose-d outside the chain. There are resilient means 18 norm-ally closing the jaws,

and there are cam roller means 20 with appropriate means connecting the cam roller means to the jaws, so that cam means'here indicated at 22 (Fig. 4), acting on the cam rollers 28, serve to open the gripper jaws as shown by the change from Fig. 2 to Fig. 4. In Fig. 4 it will be notedthat the jaw 14 is stationary while the jaw 16 has been lowered. I

Referring nowto Fig. 3, there are two pairs of jaws located symmetrically with relation to a mid-plane passing perpendicularly throughthe axis of the sprocket wheel. Specifically, there are two stationary jaws 14 located symmetrically on each side of the :chain, and two movable jaws 16 which coact with the stationary jaws 14. The.

cam roller means, in this case the two cam rollers 20 best shown in Fig.1, are also located symmetrically with respect to themid-plane of the chain. Thus the gripper is balanced with'respect to the chain, and is located as closely as possible to the chain, thus making it feasible for the gripper to be carried by a single chain.

Considering the arrangement in greater detail, the chain 12 is a roller chain having conventional outer links 24 (Fig. l) and inner 'links'26, connected by conventional pins 28 and rollers 30, the latter being spaced apart by a desired pitch. The gripper assembly comprises a pair erably made slightly wider than the standard links 26 in order to afford adequate-strength despite the presence of the slots '34.

An adjacent pair of outer linksare replaced by special outer'links These have integrally formed outwardly turned,"parts '14 which act as the stationarygripper jaws;

Accordingly a further previously referred to. A pivot pin 38 passes through the special outer links 36 halfway between the adjacent rollers 30 of the roller chain. The pivot pin 38 carries arms 40 which extend longitudinally of the chain alongside the special links 32 and 36. The movable gripper jaws 16 are bent toward the chain and are connected to the arms 40 near the pivot pin 38. In the present case the gripper jaws 16 are preferably stamped and bent out of heavy gauge sheet material, while the arms 40 are cast, and the two are secured together by means of screws indicated at 42 in Figs. 1 and 2.

The compression springs 18 are partially housed within mating holes formed in the arms 40, and for ease of assembly the holes may be closed at the end of the spring by means of small removable screws 44 (Fig. 3.) On inspection of the drawing, particularly Fig. 2, it will be seen that the spring 18 urges the arm 40 upward or counterclockwise, and with it the gripper jaws 16 upward or counterclockwise, causing the jaws 16 to press against the stationary jaws 14.

The cam rollers 20 are carried by a pin 46, which in turn is carried by the free ends of the arms 40. The pin 46 passes through the vertical slots 34, (Fig. 4) previously referred to. It will thus be evident that the slots permit vertical movement of the cam rollers. Referring to Fig. 4, the chain 12 shown is a fragment of the lower part of a long endless chain, the upper part of which is not shown except in Fig. 5. In Fig. 4 the chain is moving from right to left, and when the cam rollers 20 reach the stationary cam 22 they are pushed downward against the action of the springs, thereby opening the jaws. It will be understood that there may be two spaced cams for the two rollers, or, more preferably, a single cam which is longitudinally grooved for clearance of the chain itself or at least for the special links 32. It will be understood that the extra width of the special links 32 is of no consequence when the chain runs around a sprocket wheel, because the links 32 simply slide on opposite sides of the wheel.

As so far described it will be seen that the standard roller chain pins 28 and rollers 30 are retained throughout the chain, because special intermediate pins 38 and 46 are used for the gripper functions. Moreover, the gripper is mounted very compactly on the chain because the special intermediate pins 38 and 46 are located substnatially in the plane of the axes of the regular rollers. This, however, would cause interference with ordinary sprocket wheel teeth which would occupy much of the entire space between successive rollersof the chain.

A further feature of the invention may be explained.

with reference to Fig. 5, which shows. how the chain 13 with the gripper cooperates. with a sprocket wheel 50. For this purpose a sprocket wheel is employed in which the pitch of the teeth is only half the pitch between rollers of the roller chain. Thus two sprocket teeth instead of one fit between successive, rollers, as will be seen by the teeth 52 and 54 received between the successive rollers 56 and 58. Thus a clearance space is provided halfway between the rollers, this being the space between the teeth 52 and 54. It. will be recalled that the'pivot pin 38 is located halfway between the adjacent rollers, and similarly that the cam roller pin 46 is located halfway between its adjacent rollers. Inasmuch as these pins are. kept smaller, in diameter than the rollers, they freely enter the clearance space between the pairs of teeth.

A typical use of my chain carried gripper may be explained with reference to Fig. 9. The sheet delivery system there shown is not claimed herein, it being described more fully and claimed in a co-pending. application Serial- No. 363,253, filed June 22, 1953, and entitled Stream Sheet Delivery System. The system. receives. sheets which arecut from a continuous web by, means of a, high speed rotary cuttennot" shownhere. The sheets, arere ceived byliigh speed" belts generally designated H (only 4 theleft ends ofwhich are shown), followed by a closed loop of positively driven chain carried grippers generally designated G, which in turn is followed by slow speed belts generally designated S (only the right ends of which are shown), from which the sheets may be delivered to and stacked on a table (not shown). The high speed belts H are in pairs, there being an upper belt 62 disposed over a lower belt 64 to form one pair of belts. There are a number of such. pairs disposed collaterally across the width of the web. The high speed belts are preferably driven at a speed somewhat higher than. the web speed, while the chains G are preferably driven at web speed; Grippers 66 are carried by the chains G, which in turn are driven by sprocket wheels 68. There are a number of such chains spaced across the width of the web, and it will be seen that the chains are interleaved with the upper belts 62., The gripper jaws are opened bystationary earns 70' in a manner already explained in connection with Fig. 4, and at the cams 70 while the jaws are open a sheet is fed into. the jaws, it being understood that the various parts are driven from a common shaft, (not shown), and are properly synchronized, and timed for the intended purpose. The slow speed belts S are also in pairs, each belt consisting of an upper belt 72 and a lower belt 74. They are driven at a speed which is only a fraction of the chain speed, thus greatly slowing down the sheets. Appropriate earns 76 are located at the point where the belts 72 and 74 come together or pinch, and thus the sheet is released by the grippers just as it is slowed down by the belts. The longsloping approach portion 78 of belt 74 serves to support the slowed and overlapped sheets, particularly if long. Here again it will be. seen that the chains and belts overlap and are interleaved. This. interleaving of chains and belts across the width of the web is simplified, and close interleaving is made possible, by the fact that the grippers of the present invention are carried by a single, chain, instead of between spaced pairs of chains.

A modified form of gripper is shown in Figs. 6, 7 and 8 of the drawing. Here again the chain consists of standard outer and inner links, with standard pins and rollers, all as previously described, and here again one pair of inner linksis replaced by somewhat wider links 32' which have vertical slots 34, and which correspondv to the same numbered parts previously described. Also a pair of outer links is replaced by specialouter links 36. which are bent outwardly to form the stationary jaws. 14. These cooperate with movable jaws 16 carried by arms 40 pivoted on a pivot pin 38, all as. previously described. The gripper springs 18 may be formed and housed as previously described,.and,function in the same way. The arms 40 carry a cam roller. pin 80, which in this case is shorter thanbefore, and. carries a single cam roller; 82 located betweenv the special inner links 32. The cam. roller 82 may be given adiameter the same as that of the. standard chain rollers 30,, However, the normal position of the cam roller 82. is somewhat offset or higher than the plane of the axes of the chain rollers, and this will be seenin Fig 7.

Referringnow to Fig. 8, the sprocket wheel 84 corresponds to that previously described in having teeth with a pitch only half the pitch of the chain. Thus the space between pairs of teeth provides clearance for the pivot pin 38,, as previously described, and as will be seen in Fig. 8. However, the cam roller 82 is pushed outward by the sprocket wheel. 84, and thus moves the jaws 16 from theclosed position shown in Fig. 7 to theopen position shownin Fig. 8.

This arrangement. is especially convenient in machines in which the, jaws areto be opened while the gripper is running around: a sprocket wheel, and are to be closed while;the gripper is between sprocket wheels. However, they operation is, not: limited tothat, and; a camshoe may provided. which wntactsl the series. f; chaim rollersbetween the chain links. Such a stationary contact shoe center line of the chain.

or cam will open the gripper. If the gripper is to be opened for only a brief instant, a special idler sprocket wheel may be disposed at a desired point along the chain, as shown in Fig. 8. If the gripper is to be opened at a driving or a driven sprocket wheel, and is to be kept open for a distance following the wheel, a shoe or cam may be provided immediately following the wheel, and an extension of this shoe may be made in the form of a thin blade, and at the same time the sprocket wheel teeth may be split or cut in a plane perpendicular to the axis of the Wheel and halfway between the sides of the wheel. The thin blade extending from the contact shoe toward the wheel enters this split, and thus provides continuity in the opening of the gripper jaws. 7

Generally speaking, however, in most situations it is simpler and more convenient and flexible to use the double cam roller arrangement described in connection with Figs. 1-5.

It is believed that the construction and operation'of my improved chain gripper, as well as the method of use and the advantages thereof, will be apparent from the foregoing detailed description. The gripper is carried by a single chain. The chain may be a standard roller chain, and all of the standard pins and rollers are retained. Almost all of the links are standard, except for one pair of inner and outer links at the gripper, and even these are so designed that they may be manufactured by the roller chain manufacturer, using metal of the same thickness and character and hardness as the regular chain links. The gripper is compact and located close to the Although this requires special pins located on the center line of the chain,-clearance for such pins is provided in a simple and inexpensive fashion by so relating the chain and sprocket Wheel that the pitch length of the chain is twice that of the sprocket wheel.

It will be apparent that while I have shown the invention in several preferred forms, changes may be made in the structures disclosed, without departing from the scope of the invention, as sought to be defined in the following claims.

I claim:

1. In combination, a single roller chain having conventional outer and inner links connected by conventional pins and rollers spaced apart by a desired pitch, a sprocket wheel mating with said chain but having teeth spaced at only half the pitch of the chain, and a gripper assembly built into and forming a part of said roller chain at desired intervals, said gripper assembly having pins disposed halfway between the rollers, whereby said pins pass through the clearance provided between the teeth of the pairs of teeth received in the chain.

2. In combination, a single roller chain having conventional outer and inner links connected by conventional pins and rollers spaced apart by a desired pitch, a sprocket wheel mating with said chain but having teeth spaced at only half the pitch of the chain, and a gripper assembly built into and forming a part of said roller chain at desired intervals, said gripper assembly comprising inner links replacing the standard inner links, said gripper inner links having vertical slots therein halfway between the adjacent rollers, outer links replacing the standard outer links and having outwardly turned parts acting as spaced stationary gripper jaws, pivoted arms extending longitudinally of the chain alongside the links, movable gripper jaws disposed outside the stationary gripper jaws and connected to said arms, springs disposed between said stationary jaws and said arms to normally close the movable jaws against the stationary jaws, a cam roller pin carried by said arms and passing through the aforesaid vertical slots in the inner gripper links, and cam roller means rotatably carried on said cam roller pin.

3. In combination, a single roller chain having conventional outer and inner links connected by conventional pins and rollers spaced apart by a desired pitch, a sprocket wheel mating with said chain but having teeth spaced at only half the pitch of the chain, and a gripper assembly replacing the standard outer links and having. outwardly turned parts acting as spaced stationary gripper jaws, a

single pivot pin passing through both of said outer links halfway between the adjacent rollers and carrying arms extending longitudinally of the chain alongside the links, movable gripper jaws disposed outside the stationary gripper jaws and connected to said arms, compression springs between said stationary jaws and said arms to normally close the movable jaws against the stationary jaws, and cam roller means rotatably carried by said arms.

4. In combination, a single roller chain having conventional outer and inner links connected by conventional pins and rollers spaced apart by a desired pitch, a sprocket wheel mating with said chain but having teeth spaced at only half the pitch of the chain, and a gripper assembly builtinto and forming a part of said roller chain at desired intervals, said gripper assembly compris ing inner links replacing the standard inner links, said gripper inner links having vertical slots therein halfway between the adjacent rollers, outer links replacing the standard outer links and having outwardly turned parts acting as spaced stationary gripper jaws, a pivot pin passing through said outer links halfway between the adjacent rollers and carrying arms extending longitudinally of the chain alongside the links, movable gripper jaws disposed outside the stationary gripper jaws and connected to said arms, compression springs between said stationary jaws and said arms to normally close the movable jaws against the stationary jaws, a cam roller pin carried by said arms and passing through the aforesaid vertical slots in the inner gripper links, and cam roller means rotatably carried on said cam roller pin.

5. A combination as defined in claim 2, in which the cam roller pin is smaller in diameter than the chain rollers.

6. A combination as defined in claim 3, in which the pivot pin is smaller in diameter than the chain rollers.

7. A combination as defined in claim 2, in which the cam roller means consists of two cam rollers carried near the ends of said cam roller pin on opposite sides of the chain, whereby stationary cams may be so disposed as to cooperate with the cam rollers without interfering with the chain, the cam roller pin being smaller in diameter than the chain rollers.

8. A combination as defined in claim 4, in which the cam roller means consists of two cam rollers carried near the ends of said cam roller pin on opposite sides of the chain, whereby stationary cams may be so disposed as to cooperate with the cam rollers without interfering with the chain, the pivot pin and the cam roller pin both being smaller in diameter than the chain rollers.

9. In combination, a single chain driven by a mating sprocket wheel, stationary and movable gripper jaws disposed outside the chain and symmetrically with relation to the mid-plane of said chain passing perpendicularly through the axis of the sprocket wheel, cam roller means disposed symmetrically with relation to the mid-plane of said chain passing perpendicularly through the axis of the sprocket wheel, additional lever means on each side of the chain connecting said cam .roller means to said movable jaws, and a helical compression spring on each side of the chain between the stationary gripper jaw and the lever means for normally closing the gripper jaws, whereby cam means acting on the cam roller means serves to open the gripper jaws against the action of the foresaid compression springs, said cam roller means consisting of a single cam roller disposed between the links, said cam roller being normally displaced or offset relative to the rollers in a direction away from the grippers.

10. In combination, a single chain having conventional links connected by conventional pins, and a gripper assembly built into and forming a part of said chain at desired intervals, said gripper assembly comprising links replacing the standard links and having outwardly turned parts acting as spaced stationary gripper jaws, pivoted arms extending longitudinally of the chain alongside the links, movable gripper jaws disposed outside the stationary gripper jaws and connected to said arms, springs disposed between said stationary jaws and said arms to normally close the movable jaws against the stationary jaws, and cam roller means rotatably carried by said arms, said cam roller means consisting of a single cam roller disposed between the chain links, said cam roller being normally displaced or offset relative to the rollers in a direction away from the grippers.

11. A combination as defined in claim 2, in which the cam roller means consists of a single cam roller disposed between the gripper inner links and carried by said carn roller pin, said cam roller being normally displaced or offset relative to the rollers in a direction away from the grippers, the diameter of said pivot pin being less than the diameter of the chain rollers, and the diameter of the cam roller being substantially equal to the diameter of the chain rollers.

12. A combination as defined in claim 4, in which the cam roller means consists 'of a single cam roller disposed between the gripper inner links and carried by said cam roller pin, the axis of said cam roller being normally displaced or offset relative to the axes of the rollers in a direction away from the grippers, the diameter of said pivot pin being less than the diameter of the chain rollers, and the diameter of the cam roller being substantially equal to the diameter of the chain rollers.

References Cited in the file of this patent UNITED STATES PATENTS 

